Toward a new CAD method for MIMO multi-rate digital controllers

The author presents a novel computer-aided-design method for multi-rate sampled-data feedback systems (MRSDFSs) with many nice features including naturalness and effectiveness. Naturalness means that a control engineer can express specifications in his terms, by referring directly to signal peaks, overshoots, RMS powers, pulse responses, etc., rather than other, less direct (and more opaque) expressions (e.g. a quadratic integral in LQR or LQG). Effectiveness means that if a controller meeting the specifications exists, then the method will find it. The three main concepts for the proposed MRSDFS CAD method are: (1) shift-invariant representations for multi-rate systems; (2) parametrization of stabilizing controllers and convexity of specifications; and (3) machine intelligence and control specification language compilers. Rather than rigorously discussing each topic in depth and full generality, the author chooses a simple example and discusses each concept as it arises in the course of designing a MRSDFS